I must have missed something somewhere; I thought you were certain that you had 
fuel delivery. 
So, if the fuel pump runs and the engine fires when you spray carb cleaner into 
the intake, the injectors are not firing.
Did you try replacing the injector fuse/relay?  

LGO







-----Original Message-----
From: Eric McCord <[email protected]>
To: Bill Cardell <[email protected]>
Cc: miatapower <[email protected]>
Sent: Sat, Jul 14, 2012 6:08 pm
Subject: Re: '91 fires, won't stay on...


yes


On Sat, Jul 14, 2012 at 6:01 PM, Bill Cardell <[email protected]> wrote:


Do you have. 12 volt to the white/red wires going to the injectors? 

Bill Cardell
Owner, Flyin' Miata
Www.flyinmiata.com
1-800-FLY-MX5s
970-464-5600





On Jul 14, 2012, at 3:40 PM, "Eric McCord" <[email protected]> wrote:




Latest update. If I spray carb cleaner into the intake tract it runs. I also 
tried ANOTHER CAS. It dies when the spray is stopped. 


Eric


On Sat, Jul 14, 2012 at 5:00 PM, Eric McCord <[email protected]> wrote:

I have both, but the Data Link Lab expired. I used it for another issue and 
then didn't purchase. I have since purchased it but have not received my key 
code yet.


RPM changes on the keypad as well as INJ. I have +12 and ground at the MAP box 
with the key on.


I have also tried it with the F/P to GND in the Diagnostic connector which 
keeps the pump on and I get the same symptoms.


I just swapped out the connector at the CAS because one of the wires looked 
iffy, but no change.


Eric



On Fri, Jul 13, 2012 at 8:20 PM, Ray <[email protected]> wrote:



Do you have a keypad or datalogger?  If so, do all of the sensor readings look 
normal at key-on before cranking?  Do RPM and MAP values change as expected and 
do the injector pulse width & ign advance look normal during the brief run that 
you do get?  Do you have gnd and +12v power at the MAP box when the key is on?
 
Since the engine fires briefly but doesn’t continue to run even with the fuel 
pump jumpered to stay on, I’d guess that the plugs are firing, and the initial 
start is fueled by prime fuel but the ECU thinks that there is high manifold 
vacuum or high coolant temp and isn’t supplying enough fuel to continue running 
... or maybe the fuel map in the ECU got hosed somehow.   The FP shutting off 
when the starter isn’t running says that something is wrong with the MAP box or 
connections to it.  Normally the ECU turns that transistor on in the map box to 
keep the FP relay energized as soon as it senses RPM > 60.


From: Eric McCord 
Sent: Friday, July 13, 2012 11:39 AM

To: [email protected] 
Cc: [email protected] 
Subject: Re: '91 fires, won't stay on...


 


Swapped out both the ignition switch and CAS. No change. I have only used the 
Link. I also swapped out the fuel pump before purchasing a fuel pressure guage. 
I am getting 40 psi at the rail at all times with the key on. It is not looking 
like it is fuel related.
 
Eric


On Fri, Jul 13, 2012 at 2:35 PM, [email protected] <[email protected]> wrote:

A long shot here, but  it may be that the ignition switch is faulty, allowing 
to to start the car and then losing electrical contact, or perhaps the current 
from the ignition to the CAS has been interrupted.  WAIT!  You are using the 
Link now, but did you EVER use another method of engine management?  Did you 
use an MSD?  I recall long ago having a problem develop after I upgraded from 
the Bell Sys II to full FM II spec with link, and it turned out that old wiring 
for the MSD unit had developed a short (or some problem... was years ago!)
 
LGO
 

 

-----Original Message-----
From: Eric McCord <[email protected]>

To: Mark Phillips <[email protected]>
Cc: miatapower <[email protected]>


Sent: Fri, Jul 13, 2012 11:54 am
Subject: Re: '91 fires, won't stay on...


No luck. I just replaced that transistor and it is still doing the same thing. 
 
Eric


On Fri, Jul 13, 2012 at 10:41 AM, Eric McCord <[email protected]> wrote:

I am off to the Shack. 
 
Eric 



On Fri, Jul 13, 2012 at 10:39 AM, Mark Phillips <[email protected]> 
wrote:

Yes. 



On 07/13/2012 10:28 AM, Eric McCord wrote:

on yours it was T2? Did you just replace the transistor to get it back up and 
running? 
 
Eric


On Fri, Jul 13, 2012 at 10:25 AM, Mark Phillips <[email protected]> 
wrote:

The relay has 12 volts applied to one side of the coil with the ignition on. 
When you jump F/P to GND you are taking the other side of the relay coil 
straight to ground bypassing the transistor. Normally the transistor performs 
this grounding function (sinking current). T2 also interacts with other 
circuity in the MAF box.

This happened to me about 4-5 years ago on my '92.

Mark 

 

On 07/13/2012 10:00 AM, Eric McCord wrote:

When I jump out the F/P to GND the pump stays on but I still have the same 
symptoms. If that transistor drives the relay but I jump it out should that not 
run? 
 
Eric


On Fri, Jul 13, 2012 at 9:54 AM, Mark Phillips <[email protected]> 
wrote:

Hi Eric,

I sent this out earlier but didn't see it repost. I apologize if its a repeat.

There is a transistor in the Link box that replaces the AFM;  it drives the 
fuel pump relay. It is an NPN transistor, is marked "T2" and may have failed. 
About $1.50 and a soldering iron to replace.

Mark Phillips 



On 07/13/2012 09:40 AM, Eric McCord wrote:

I just swapped out the CAS and same symptoms. If it's a bad MAF box where can I 
get one of those? Since my Baja went down the Miata has been my only 
transportation and Kaitlyn and I are leaving in a week and a half for the 
dragon and our road trip. 
 
Eric


On Fri, Jul 13, 2012 at 9:18 AM, Ray <[email protected]> wrote:



Can also be that one of the two signals from the CAS is not there.

 

From: Eric McCord 
Sent: Thursday, July 12, 2012 6:21 PM
To: [email protected] 
Cc: [email protected] 

Subject: Re: '91 fires, won't stay on...


 

Just checked that connector. It looked fine, I reseated it and still have the 
same symptoms.  
 
Eric


On Thu, Jul 12, 2012 at 9:07 PM, [email protected] <[email protected]> wrote:

Have you checked the manifold pressure connection (heck! I think that's what 
its called - I can't remember!) ?   If it comes loose, it may begin to fire and 
then die.  On mine its the small box with the AFM-like connector (multi-pin) on 
the driver's side.   
 
LGO



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